"use strict";
const axios = require("axios");
const urlJoin = require("url-join");
const semver = require("semver");

function getNpmInfo(npmName, registry) {
  if (!npmName) {
    return null;
  }
  const registryUrl = registry || getDefaultRegistry();
  const npmInfoUrl = urlJoin(registryUrl, npmName);
  return axios
    .get(npmInfoUrl)
    .then(response => {
      if (response.status === 200) {
        return response.data;
      } else {
        return null;
      }
    })
    .catch(err => {
      return Promise.reject(err);
    });
}

async function getNpmVersions(npmName, registry) {
  const data = await getNpmInfo(npmName, registry);
  if (data) {
    return Object.keys(data.versions);
  } else {
    return [];
  }
}
function getNpmSemverVersions(baseVersion, versions) {

  // baseVersion ^1.0.3   >=1.0.3 && < 2.0.0
  // 表示 version 是在 baseVersion 范围内
  // https://juejin.cn/post/6844903516754935816
  return versions
    .filter(version => semver.satisfies(version, `^${baseVersion}`))
    .sort((a, b) => {
      return semver.gt(b, a);
    });
}

async function getNpmSemverVersion(baseVersion, npmName, registry) {
  const versions = await getNpmVersions(npmName, registry);
  const newVersions = getNpmSemverVersions(baseVersion, versions);
  if (newVersions && newVersions.length > 0) {
    return newVersions[0];
  }
}

function getDefaultRegistry(isOriginal = false) {
  return isOriginal
    ? "https://registry.npmjs.org/"
    : "https://registry.npm.taobao.org/";
}

async function getNpmLatestVersion(npmName, registry) {
  const versions = await getNpmVersions(npmName, registry)
  if (versions) {
    return versions.sort((a, b) => semver.gt(b, a))[0]
  }
  return null
}
module.exports = {
  getNpmInfo,
  getNpmVersions,
  getNpmSemverVersion,
  getDefaultRegistry,
  getNpmLatestVersion
};
